Office 365 includes hosted versions of SharePoint, as well as Exchange (email) and Lync (IM and meetings).

The deal calls for HP to host Office 365 for its so-called "private cloud" customers, and to act as a reseller for the Microsoft-hosted version.

This deal offers the double whammy of letting HP stick it to Cisco, one of its biggest rivals. Cisco earlier this week introduced its own cloud-building offerings, a massive collection of hardware, software and services it calls CloudVerse. Where Cisco has VMware and EMC as partners, HP has snagged Microsoft.